Lewis Henry Morgan went so far as to divide the earlier two stages into three sub-stages. Each of his stages are defined by some development of technology. So, here are his 'official' definitions of civilization, barbarism and savagery.

This idea is outdated! Anthropologists no longer consider society to 'evolve' in the way biological animals do. A society without iron isn't 'less developed' than one with iron. This node is here as a historical curiosity, not a study guide for racism.